As described in issue #54 the core should allow allocations without a resource linked to it.
K8 has a concept of different QOS pods. The quality of service definition is linked to the way resources are requested by a pod. QOS is equivalent/linked to oversubscription as we know it in YARN.
Allocations that have no resources have a far deeper impact and also affects placement and pre-emption. We need to be able to properly tag and track them in the core scheduler.
A shortcut solution to allow scheduling of BestEffort QOS pods (pods without resource requests) was added to the k8shim via PR apache/incubator-yunikorn-k8shim#52. That change should be rolled back when we support zero resources on a request.